A variety of portable basketball systems are commercially available. One portable system, described in U.S. Pat. No. 5,248,140 issued to Matherne et al., provides several important advantages. The system includes a pole attachable to a backboard at one end and to a hollow ballast-receiving base at the other end. In the system's assembled state, several pole sections are joined to form the pole, and a basketball goal ("hoop") is mounted on the backboard. The base is filled with a ballast such as water or sand to provide stability to the assembled system.
In the system's disassembled state, the base is emptied of ballast, making the system light in weight and hence facilitating easier and more cost-effective storage and shipping. The base is shaped with contours that receive and retain the system's backboard, goal, and pole sections when the disassembled system is packed within a shipping container. The base contours impede shifting movement of the system parts within the container during shipping, thereby reducing the risk of damage to the system during transit. The base contours also permit the entire system to be packed for shipment in a relatively flat shipping carton, thereby reducing the space required to hold the disassembled system.
Basketball backboards for either portable or fixed-in-place basketball systems may be formed with a variety of materials and processes. Backboards formed of wood, steel, acrylic, graphite, aluminum, and fiberglass are all known in the art. Manufacturing processes such as injection-molding, blow-molding, and other molding methods, as well as bonding, cutting, and coating processes are also well-known.
Regardless of the material and processes used, or the type of basketball system a backboard is meant for use with, several backboard qualities are important. The materials and processes used in forming a backboard preferably have a relatively low cost, provide easy shaping of the board during its manufacture, create a board that is strong, impact-resistant, and weather-resistant, and provide uniform rebounds from the finished backboard. In addition, a backboard which is part of a portable basketball system is preferably light-weight to facilitate portability and to reduce shipping costs.
Wood was originally the material of choice for forming backboards, because it has a relatively low cost and may be easily shaped during manufacturing. Indeed, the tools required to shape a wooden backboard are readily available even to household consumers. Wood also has sufficient strength, rigidity, and impact-resistance to serve as a backboard when laminated into sufficiently thick plywood sheets. However, wood is much less weather-resistant than materials such as acrylic, graphite, and fiberglass. Nor are the necessarily thick wooden backboards light-weight enough to be attractive for use in portable basketball systems.
Although steel backboards are strong and rigid, they are relatively difficult and expensive to manufacture. For instance, costly specialized machinery is required to shape steel into backboards. Steel also rusts, so a protective coating must be applied to a steel backboard to maintain the backboard's attractive appearance if the backboard is exposed to the weather, as many backboards are. The addition of such a coating increases both material and manufacturing costs. Moreover, steel is a heavy material and therefore is not favored for use in portable basketball systems.
Fiberglass is relatively inexpensive, easy to shape, light-weight, and weather-resistant. Unfortunately, fiberglass is not sufficiently impact-resistant to withstand prolonged and vigorous use. Acrylic and graphite materials are both impact-resistant, they each weather well, and they are easily shaped by conventional processes such as injection-molding or resin transfer molding. Acrylic and graphite materials are also relatively light-weight. However, these materials are significantly more expensive than fiberglass. Each material is also heavy enough to encourage attempts to reduce the backboard's weight still further.
Accordingly, several designs attempt to provide a light-weight molded backboard which is nonetheless strong enough to resist extensive energetic play and which provides uniform rebounds. The simplest approach provides a backboard which is essentially a thick sheet of the material in question. The backboard has a flat front face spaced apart from a flat rear face. Except for holes used to mount the basketball goal to the backboard and to mount the backboard to the pole, the backboard is solid between the front face and the rear face.
Forming the backboard as a sheet facilitates manufacturing. However, the sheet must be relatively thick to provide sufficient strength for the backboard to withstand repeated impacts from a basketball. Because the sheet is solid, making the sheet thicker may significantly increase the weight of the backboard. The increased weight in turn increases the cost and effort required to ship or reposition a basketball system which includes the backboard.
Another approach forms the backboard as a hollow sheet. The backboard still has a flat front face and a flat rear face, but these faces are separated at least in part by a chamber within the sheet. By not including material everywhere within the sheet, this approach may substantially decrease the backboard's weight. However, the chamber also decreases rigidity. Such a backboard may flex rather than properly rebounding the basketball. Increasing the thickness of the front chamber wall will increase the backboard's rigidity but also increases its weight.
A variation on the hollow sheet approach is to fill the chamber with a material such as polyurethane foam which is lighter than the material used in the chamber walls but which nonetheless adds strength to the backboard. However, such fill materials tend to lose adhesion to the chamber walls over time and after repeated impacts from basketballs striking the backboard. Preferred fill materials may also add significantly to the backboard's cost.
One approach succeeds in reliably bonding a urethane layer between two thin outer walls of aluminum. This produces a "sandwich" backboard which is not substantially heavier than fiberglass and which provides consistent rebounds. However, both the materials and the tooling required make manufacturing such a backboard relatively expensive and time-consuming. Moreover, sandwich backboards may be permanently dented by impact with anything more rigid than a basketball, such as during shipping or installation.
In addition, any approach which makes the backboard a sheet with two flat faces, whether hollow or not, fails to take advantage of a critical difference between the two faces: the basketball normally hits only the front face. Thus, the rear face need not be flat.
Accordingly, a different approach forms a backboard from a wall of material which is thinner than typical sheet backboards formed with the same material. The front side of the wall has a flat face which receives the impact of basketballs during play. The rear side of the wall is not flat, but is instead reinforced by ribs in an effort to compensate for the loss of strength and rigidity caused by thinning the wall. The ribs are typically integral and unitary with the wall, and are typically molded in place when the wall is molded.
Various rib patterns are employed. One pattern is a simple X whose center is positioned near the center of the backboard. Although this pattern adds strength to the board, it does not provide relatively uniform rebound. Large sections of the backboard's front face are not directly reinforced by one of the ribs and therefore have less rigidity and a greater ability to absorb kinetic energy from the basketball. Thus, a basketball which strikes one portion of the face at a certain angle and velocity may rebound quite differently than would an identical basketball which strikes a different position on the face at the same angle and velocity. The resulting inconsistent rebounds are generally undesirable.
Another pattern includes a group of parallel ribs extending from one edge of the backboard to another edge. Such backboards tend to flex or break along the line of one or more ribs. A variation on the parallel rib pattern includes two or more groups of parallel ribs to create a rectangular or triangular grid of intersecting ribs. That is, the ribs in each group are substantially parallel to one another, and each group is transverse to another group. A pattern of this general type is illustrated in U.S. Pat. No. 3,788,642.
Regardless of the number of groups of parallel ribs used, the rib pattern in such backboards is substantially uniform across the entire backboard. In particular, no correction is made for the fact that portions of the backboard are anchored to the pole or to the hoop. Portions of the backboard near the mounting points of the pole and the hoop are reinforced by ribs placed in substantially the same pattern as the ribs that reinforce more distant portions of the backboard. The more distant backboard portions, which are reinforced by ribs but not directly anchored to a pole or hoop, therefore rebound differently than the portions which are both reinforced and anchored.
Other backboards therefore employ ribs arranged in a complex network of interconnected lines designed to provide consistent rebounds. Unfortunately, using ribs in any pattern limits the materials used in forming the backboard to those materials such as fiberglass, graphite, and steel which have sufficient tensile strength and rigidity for ribs to provide adequate reinforcement. Disadvantages of these materials are discussed above. Other materials, which have superior impact-resistance but lack sufficient rigidity for use in ribbed backboards, are unfortunately ruled out by the various ribbed backboard designs.
Thus, it would be an advancement in the art to provide a basketball backboard formed of a material which has better impact-resistance than fiberglass at a comparable weight and cost.
It would also be an advancement to provide such a backboard which gives consistent rebounds during play.
It would be an additional advancement to provide such a backboard which is weather-resistant.
It would also be an advancement to provide such a backboard which does not dent easily.
It would be a further advancement in the art to provide such a backboard which is easy to manufacture using conventional methods.
Such a basketball backboard is disclosed and claimed herein.